添加石墨烯的磷酸铁锂锂离子电池的性能

Performance of LiFePO_4 Li-ion battery with graphene addition

向磷酸铁锂(Li Fe PO4)正极材料中添加石墨烯,研究石墨烯添加量对Li Fe PO4正极锂离子电池性能的影响。石墨烯添加量为20%时,电池的低温性能最佳:与常规电池相比,正极活性物质的0.50 C比容量(2.50~3.65 V)从111.07 m Ah/g提高到135.83 m Ah/g;内阻从20.37 mΩ减小到8.26 mΩ;3.00 C倍率放电平台为3.09 V,提高了0.15 V;低温-20℃可放出额定容量的74.20%。添加石墨烯的电池的不可逆容量较高,会降低电池的首次充放电效率和循环性能,其中添加20%石墨烯时,0.10 C首次充放电效率为92.29%;0.20 C循环50次的容量保持率仅为65%。

With the addition of graphene in cathode material of lithium iron phosphate （LiFePQ）, the effect of grapheme additive amount on the performance of LiFePO4 cathode Li-ion battery was studied. When the amount of graphene was 20%, the low temperature performance of the battery was the best. Compared with the common battery, specific capacity of cathode active material at 0. 50 C in 2. 50 -3.65 V was increased from 111.07 mAh/g to 135.83 mAh/g, internal resistance was decreased from 20. 37 mΩ to 8. 26 mΩ. The discharge voltage platform was 3.09 V, increased 0. 15 V. The battery could release 74. 20% of the nominal capacity at low temperature - 20 ℃. The addition of graphene would produce an higher irreversible capacity in battery, it would also reduce the initial charge-discharge efficiency and cycle performance. With the addition of 20% graphene, the initial charging efficiency was 92. 29% for 0. 10 C,the capacity retention rate was only 65% after 50 cycles at 0. 20 C.